This application claims priority of Taiwan Patent Application No. 090221942 filed on Dec. 14, 2001.
The present invention relates to a key structure and a keyboard. More particularly, the present invention relates to a key with a limited stroke and a scissors-shaped member.
Keyboards are widely used with various devices, such as computers, to input characters and numerals.
To make a key on the keyboard easy to depress, the key is usually designed to function no matter where a force is exerted on the key cap. In other words, even though the force is exerted on the edge of the cap, it is equally distributed over the entire surface of the cap. Generally, to this purpose, a scissors-shaped frame is used to form the key structure. It is especially true for the keyboard of portable computer device requiring minimum space, such as super-slim portable computer.
Controlling stroke of key is important to a keyboard, especially to a keyboard used with a portable computer device. Conventionally, because the scissors-shaped member described above may not limit the stroke of key, two methods are used to limit the stroke. In the first method, the stroke is limited to the height of elastic component of the key. However, this method may not precisely control the stroke.
In the second method, a groove is arranged on a base of the key, and a latch is connected with an edge of the cap through the groove. When the cap is elevated to a predetermined position, the latch engages with an edge of the groove to stop the cap. This method may precisely control the stroke; however, it increases the time and difficulty of manufacture process.
Accordingly, problem of the stroke limitation still exists.
The first aspect of the present invention is providing a key with limited stroke and a scissors-shaped member.
Another aspect of the present invention is providing a key with limited stroke by using a relatively simple manufacture process.
Another aspect of the present invention is providing a keyboard including the key described above.
The key structure of the present invention includes a base, a scissors-shaped member, and a cap. The scissors-shaped member is disposed on and coupled to the base. The scissors-shaped member also includes a first frame and a second frame. The first and second frames respectively have a first and a second protrusions. The cap is disposed on and connected with the scissors-shaped member. The cap may vertically move relative to the base due to a relative rotation between the first and second frames.
In a first embodiment, when the cap is elevated to a first position, the fist protrusion engages with the second protrusion to stop the cap. Thus, the upward stroke of the key may be limited.
In a second embodiment, when the cap is depressed and lowered to a second position, the first protrusion engages with the second protrusion to stop the cap. Thus, the downward stroke of the key may be limited.
In a third embodiment, the second protrusion further includes a first end and a second end. The first protrusion engages with the first end to stop the cap while the cap is elevated to the first position. The first protrusion engages with the second end to stop the cap while the cap is depressed to the second position. Thus, both the upward and downward strokes of the key may be limited.